Circuit breaker



Dec. 28, 1943.

J. W. MAY

CIRCU Filed April 4. 1942 IT BREAKER 2 Sheets-Sheet l Dgec. 28, 1943. J. w. MAY

CIRCUIT BREAKER Filed April 4, 19.42

2 Sheets-Sheet 2 mvENToR .fo/7n 14K/Way.

BY @W @M Patented Dec. 28, 1943 S PATENT OFFICE cmcm'r pasarme John W. May, Durham, N. C., assigner to West-- inghouse Electric a Manufacturing Company, EastPittsburgh, Pa., a corporation of Pennsyl- Application apra 4, 1942, serial No. 431,631

v1i claims. (cuco-109) This inventionrelates to circuit breakers and more particularly to shock proof circuit breakers of the type which are automatically tripped open in response to predetermined overload conditions. One object of the invention is to provide a cir--V cuit breaker in which an improved device prevents the automatic opening o! the breaker in response to shocks orfjarring forces to which it may be subjected. ff l Another `objectofthe invention is to yprovide 'a circuit breaker having an improved 1device oper-- able in response to shocks or jarring forces, which applies a force Vtofthe trip device of the breaker opposing tripping action 'of the trip device.-

Another vobject of `the`inventionisto provide a circuit breaker4 *with a' normally lstatic device which is eiIective only upon the'occur'rence of a jarring force to prevent tripping 'the breaker in response tojarring forces. j 'ff A:

Anothercbjet of the invention is topfovide a circuit breaker having a shock proof device comprising a "minimum number of parts. :f

1 Anou ,object of the invention is toprovide'a y,

circuit breaker having a `shock proof device which a plurality oi members are disposed for movement in opposite directions and are operable in response to shocks occurring in either of the opposite directions to prevent tripping' the breaker.

' Another object of the invention isto provide a "trip device for a circuit breaker with an improved shock prooi device in'which'lapair of unbalanced ni'embers deach isop'erable independently of the other in responsejto sudden jarring forces to apply a forceopposing tripping of breaker.

The novel features that are considered characteristic of the invention are set Iorth in partic-y ular inthe appended claims, the invention itself', however, both as to structure and operation, together with additional objects and advantages thereof, will be best understood from the following detailed description of one embodiment thereof when read in conjunction with the accompanying drawings, in which:

Figure l is a vertical sectional view through the center pole of a three pole circuit breaker embodying the features of the invention;l

Fig. 2 is a fragmentary sectional view taken on line II-II of Fig. 1;

Fig. 3 is a vertical sectional view through the trip device taken substantially on line III--III of Fig. 2; and

Fig. 4 is an enlarged fragmentary view of the shock prooi device showing one of the shock proof members in the position assumed in response to a sudden shock or jarring force.

Referring to Figure i of the drawings, the circuit breaker is provided with an operating mechanism common to all of the poles which is ing thrioughn an opening in theconnector Il and through openings in Vthe sides ot the V:ix-aine I6 'pivotally supportsa pair `voi'spaccd arms Il (only one being shownlhaving their free ends integral with a contactarml i'or thevcenter pole. The contact arms, (Fig. l) for the 0uterpoles are identical-with the arm I0 for the center polebut are notvprovided with arms Il. The contact arms fcgiwtheV puter poles are rigidly secured to a tie bar l1 which extends across all of the'poles and which is clampedfto the center pole contact arm I0 by means of a split clamp 10 and a screw Il. The three contact arms 30 -are ythus mechanically connected for movement together. Rectangular atubes 68 of insulating material Vbetween the tie bar `6'! and contactarme 30 for the severalpoles serve to insulate the three movable contact .:arms and their associated contacts from the tie bar 61. l l.

The movable contact'structures and the stationary contacts for the several poles are alike and thereioreonly the center pole contact means has been shown. The contact arm 30 i'or the center pole pivotally carries a main movable contact member 41 and a movable arcing contact member 55. The main contact member 41 is pivoted on a pivot pin I9 supported in projections 5i .of the contact arm 30, and the movable arcing contact member 55 is pivoted on a pivot pin 5l supported in projections I9 oi' the arm I0. The main movable contact member 4l carries a contact 33, and a contact 35 is secured to the arcing contact member 65. These contacts 33 and 35 are adapted to respectively engage fixed contacts 3B and 3l secured on a conductor 4I which is in turn secured to the base Il by means of bolts 43. The conductor 4i extends upwardly and is bent at right angles. the bent portions extending 2 assauts through an opening in the base I I to form a ter. minal connector It.

A spring 63 compressed between s. spring seat on the contact arm Ill and a spring seat on the main contact member 41 provides contact pressure for the main contacts "-39 when the contact arm is in the closed position. Contact pressure for the arcing contacts 35-31' is provided by a spring 63 surrounding a rod 8| pivotally connected to the arcing contact member I! and slidable through an opening in a spring seat on the contact arm t0. The spring B3 is compressed between a washer B5 seated on a shoulder on the rod ti, and the spring seat on the contact arm lli. The rod 6| has a nut 1S onthe outer end thereof which acts to limit counterclockwise rotation of the arcing contact member Il about its pivot when the contact arm 3U is moved to open the contacts. Counterclockwise movement o! the main contact member 41 is limited by a projection il thereon striking the body of the contact arm l0. The adjustment of the nut 1I on the rod Il is'such' that the arcing contacts 35-31 open after the main contacts IH! open during an opening operation oi the circuit breaker, and

close before the main contacts iclose during a closing operation. l l

When the contact arm 80 is operated to open the contacts. the arc across 'tbarcing contacts Sl-I'I resulting from the ruptureofthe current is drawn'into an arc extinguisher indicated generally at 1B where it is cooled and extinguished. any suitable arc extinguisher may be employed. theone illustratedcomprisinmgenerally, a stack or slotted plates (not shown) of magnetic material .disposed adJacent the paths'oi' travel oi-each ofthe Bl'ing contacts 3B. 'Tle plates serve to draw the Vare towards the ends or Athe slots where it is broken up into 'a plurality of short arcs which are-quickly cooled and extinguished.

- LThe movable arcing contact member 85 is connected by a'nexible shunt "conductor 11 to the main contact member I1, and s :hcnther flexible shunt conductor I9 connects the main contact member Il to the connector l1. The connector Il' tor the-center poleis secured tothe crossmember Il of the frame by the bolts 2l, and the connectors 2l ior the outer poles (not shown) are bolted to the base Il with a spacer (not shown) between the base and each of these connectors `in order to align the members 21 of the outer poles with the corresponding member I1 tor the center pole. A conductor ll. secured to the connector 21 by means of screws Il extends downwardly therefrom and is bent at right angles. The horizontally disposed portion of the conductor extends between the legs or a U- shaped tripping magnet core III and projects through an opening in the base Il where it forms a terminal connector It which, together with the terminal connector 4t, serves to connect the pole of the breaker in an electrical circuit. Conductors similar to the conductor Il are connected to the connectors 21 of the outer poles and form the lower terminals ot the outer poles.

The electrical circuits for the several poles ot the breaker are essentially the same. The circuit o! each pole extends from the corresponding terminal connector l! through the conductor I I, the main contacts il-tt, the main contact member Il. the iiexible shunt conductor 1I, the connector 21, the conductor 8l to the terminal connector II. The circuit for the arcing contacts I'I-II extends from the terminal connector 45. through the conductor 4I, the arcing contacts l`l3l.

contact member il, the exible shunt conductor 11, the main contact member l1, and through the previously described circuit to the terminal connector Il,

The contact arms I0 are biased in a clockwise or opening direction by means of a. pair of springs l! (only one being shown). These springs are tensioned between the center pole contact arm It and a fixed pivot Il supported in the main frame I6. In the closed position o! the breaker. the center pole contact arm 80 and consequently all of the contact arms are releasablv restrained in closed contact position (Fig. 1) by means of a toggle and linkage mechanism which is collapsible tol cause opening of the contacts. The toggle and linkage forms a part or the common operating mechanism.

This collapsible linkage includes a lever tl plv otally mounted on a iixed pivot Il supported on the main frame II. The lever Il comprises a pair or levers rigidly connected by an integral cross bar lil, and is operatively connected to the support arms` Il oi' the center pole contact arm til by a main operating toggle comprisingtoggle links il and Il. The toggle link I3 has one end pivoted ons pin IBI supported on the lever II and the link i! is plvoted on a pivot pin I9 on the arms Il. :The links It and It are pivotally connected by a knee pivot pin l1. The toggle. link Il comprises a pair or rigidly connected by means of anlntegral cross bar III.

The end or the lever Il isgpivotally connected foy-means or a link lill to one arm o a lever III pivoted on the fixed pivot l'l. The o r arm ot-thefleveryllli is pivotal!! connected a toggle link. |01 of a tripping toggle comprising the link lll and a toggle link l0l..'1'he link ill is pivotedon a nxed pivot .I il Supported on the trame Il and comprises a pair o! links lioined nearthe pivot ill by a yoke |23 provided with projections lllv and AIl'l. The toggle link Il! -comprisesa pair of linksconnected by a yoke III having la bentportion to which is secured an extension lll of insulating material. The toggle links I'l and IM-arepivotally connected by a knee pivot pin ill. 'I'he purpose of theextem' sion III y.is to 'cooperate with a part connected to a manually operable, handle III to manually trip the breaker in a manner to 'be more fully described later. The lever lill and the link "il f tion. the main operating toggle It-ti is overcenter above a line through the center of the pins lil-IUI, and a second toggle, one link or which comprises the overcenter links 03-85 and the other link of which comprises the lever Il, is overcenter above a line through the center of the pins 88 and il. The overcenter movement oi' the main operating toggle 83-96 is hunted by the projecting end of the link 93 engaging the cross bar IIB ofthe link il.

With the main operating toggle BS-BS and the toggle comprising the links 83-95 and the lever B9 in the overcenter position, as shown in Fig. l. the springs B5 bias the lever I9 in a clockwise direction. Clockwise movement oi' the lever B8, however, is normally prevented by the trlppirl` toggle IBL-M9 which is overcenter to the left of a line through the center of the iixed pivot lil and the point of connection o! the toggle link |01 with Vthe leveriiii. 'Iihe toggle Inl-iii! is biased toits overcenter position by a spring. |28 tensioned between the yoke H9 and the fixed pivot H3. The overcenter position of the tripping toggle Inl- |08 is adjustably determined by the projection |25rof the yoke |23 engaging an adjusting screw |28 in the cross member 25 of the frame. The tripping toggle |01- ill! in its overcenter position, acting through the lever lili and the link |03. prevents clockwise movement of the lever B9 and consequently holds the movable contact assemblage in the closed contact position against Athe biasing innuence of the springs 85. n 4. ,f

The tripping toggle lill-|08 is adapted to be moved oven-center outvirardlyinI it direction to cause its collapse to effect opening ot the contacts by means of an overioadltrip device indicated generally at |33 (Fig. l1). VThe trip device isoperable in response to overload currents in the circuits of the breaker to actuatea trip rod llifand cause, collapse-pi fthe tripping toggle illi--ili` The triprod Il! is slidable vertically through Aa. shunt trip coil (nm shown) enclosed in a casingi attached to themain trame il.

The shunt trip coil Iormsan additional tripping means for tripping the breaker. shunt coil is adapted to be energized from ,a suitable source. controlled from a remote point and in a manner well knownz in the art. Itooperate the trip rod andtripthebreaker.; i. q l- 1 A operated either by the shuntcoilonby the overload trip device |38. the trip rod |38 is thrust -upwardly and .strikes -the -projection |21 yoke. lll-and rocks thetoggie link .lill4 clockwise about the liked, pivot iii. This movemento! the linkin causescollapse ci.' thetrip- Pins toggle .lill-IN permittinslockwiseimovee mentor the lever iis'which-permits the sprinss.

ll to rook the movable contact `assemblage clockwise tonnen thecontacta. t.

The main operating toggle ll-lt-dces not immediately, but the force oi'lthe s111111!! 8l applied through the contactvarm ill-Ii and the main operating toggle causes collapse ofthe .toeslecompnsms msnm uvas and the lever len which results in a clockwise movement ol the lever I8. movement is transmitted through the inland the leverL |06 tocomplete lthe collapse ,ol the tijippingtoggle lill-|00.V -V it. *uw

YThel .clockwise or opening fmovement A contact ,armi III islarrested by projections (not shown) thereon striking portions ill of theframe I6. Atthis time thefrebound olAthe inertiafo! the'jmain operating td'gleJl-SI andv the parts crtnelinkasess. luiandlosstsrts the main operating toggle overcenter in a direction to cause its collapse. By the time the knee pin" ofthe toggle has paed overcenter below the line ll- IUI the weight ofthe parts act to complete the collapse ci' the toggle 93-95 and causes the linkageil, I U3. and the tripping toggle Wifi to be automatically reset to their normal position. The main operating toggle 93-'-ii5 remains in collapsed condition until the contacts are closed.

The contacts are closed manually by operation o! the previously mentioned handle lli.' The handle is rotatably mounted in a bracket I 43 of insulating material secured to the outer end of the main frame i8. operatively connected to the mechanism (not shown) operated by the handie, is a link ill. The lower end of the link lll is recessed and straddles a pulley-shaped projection |53 rigidly secured on a cross member lli` rigidly connecting the outer ends of a pair of spaced contact closing levers H5. These levers are disposed on the outside of the frame Il and are pivotaily supported on the ends or the nxed pivot Diwhich project beyond the sides ofthe frame. The-inner ends o! the levers |48 are rigidly connected by a cross member i, Spaced projections |52 extending from the center portionof` the cross member |49 support a pivot pin iiiupon which is rotatably mounted a roller ill.

.The contacts are closed manually byclockwise rotation ofthe handleilL This movement of the handle, through connections-(not shown) thrusts the link Iii downwardly and due to its engagement iwith the projection IBI. rotat the closing lever |45 in a clockwise direction. t During 4this movement oi' the lever M5, the roller ill engages the link, ofthe now collapsed main operating toggle 93-95 andmoves thistoagle toits oversety position. `Since at this.` time the i tripping cognomi-lus has been restored to its overcenterposition, rotationof' the lever Il is prevented and consequently the force applied by the roller |55 to straighten the toggle II-ll rotates the contactarlo 30, counterclockwise to close the contactsl and to tension the springs Il. The clockwise movement of the closing leveri ill moves the i toggle 83`95. overcenter A,above 'the line Il.l|ll so that the contacts are'held in the closed position until. the breakeris-again tripped. VUpon releas'eoi 'the handle Il 'i following a contact closing operation?. "a` spring iii! tensioned between Jtlieclosing lever ill andthe frame il restores .th l.leverr [il in fitJ conterclockwise direction.V` 'rnismovfement ofthe lever mand the Pl'Oiection* |53 .thrusts the link `III p upwardlyy to restorethehandle lli toits neutral position. v l Theplosing' leverili may beoperated to automatically close the" contacts through',` the agency pradrriotor |39 (Figli) mountedon a plate at,- tached toithesideoflthe framefi.v The'motor m new 'energized yfrom any sume-source. liihesienertiz. .the ,motorie dvtefithrush irsuitablegirivingcoimection; to'rotateacrank juafgrnisjdisc cames jan aritirricuonl rouer III which engages a cam tace 1,3?. on an arm Il l secured toone'sideof the closing lever '|45 and rotatesthearm and the'closingleyer ilfclockwise toellect closingof the contacts in thepreviously described manner. As soon asfthe, roller il! passes outof engagement with the'arm gl, the spring IES acts' to restore thegle'verillto its normal position.I 'The motor il! isjdeenergiaed by a suitable limit switch, (not`shown) L fl'he jcirchuit breaker may 'be tripped manually by rotationy ofthe handle "147| tl-ir ugh 'a small anglein acounterclockwise direc ondrom its neutral position. When the handle is rotated in tripping direction, a projection (not shown) on the link |6I engages the extension |2| on the yoke Ii! of the toggle link |01 and rocks the link counterclockwise about its point of connection with the lever |05. This moves the tripping toggle inl-|09 overcenter in a. direction to cause its collapse and etiects opening ofthe contacts in the previously described manner.

As previously stated, the triprod i!! `is operated to eii'ect tripping ci' the breaker by means of a current responsive trip device III. There is a trip device |33 provided 'for at least two of the poles of the breaker but since the trip devices are alike only the one for thecenter pole will be described.

l rEach trip device includes the U-shaped magnet core IBI and a frame comprising substantially their outer ends by a yoke itl. The members A |33 are lprovided with mounting feet |31, and

bolts |03 extend through openings in the feet |31 and in the magnet core |6| and in the base ,torigidiy secure the core -and frame to the base. "A trip lever |13 is pivotaily supported on a pivot |13 mounted in the frame |63. The trip lever |13 comprises a pair oi spacedilevers having an amature |18 secured to one end and being rigidly connected by a yoke |11 at'the other end. The' trip lever |13 is biasedagainst operation by the magnet IBI, by means o! a pair of springs ill (Figs. i, 2 and 3) having one end secured to the yoke |11 and theother end attached to a verticallvv'movable plate |93. `The plate |23 cooperateswith an adjusting screw |33 which is provided with a knurled head |31 bearing against tlrejbottom side voi a formed projection |33 oi the frame yoke |65. "Rotationof the screw |33 moves the plate |93 and thereby adiusts the tension of the springs |8| to vary the tripping point oi' the breaker. -A scale plate 203, (Fig. 3), supported on spaced projections 20| of the yoke |66, bears indicia indicating the'adjustment'oi the springs alli. ortho tripping pointn 9! 'the breaker! trip "bai-fit1 isrctatably'supported in= a bracket islsecuredgto' the casing |30 for the nunttnpcou. The mp barextendssemss an or theppies er vthegtst-ecker and is provided with anvarin' Il! ioreachpolethc center oneof the suns being in alignment with the lower end o: thejtrip rod |33. l 1 Y ,mounted inrleach o i.'l theykes illin alignment withthefcorrespondlng armV |33. Normal rated. current .flowing through'thecircuit otthegbreaker. including the conductor Il, causes slight energization ofthe magnet isi but not jumcient to overcome the tension of the 'snrinstlill g turrehtgabove a predetermined value in the cir-L4 Ygglarii liole. th'e owofcurrent through the p oii'l g conductor 3| causes energization o! the Ymagnet sumcient to overcome the' springs ,ill and attract the amature K,|19 rocking the trip lever,i 13 Ycoun'te'rcloelrwise.v [Atl this novement ot the ,trip lever |13,the screw i3! 'rotates the arm |33 'and thetrip bar |l1 iii a clockwise direction andthrusts the trip rod ,|35 upwardly to trip the breaker in the previouslyjdescribed manner.

The overload trip device '33 includes a dash pot timedel'aydievice o! the suction disc type removably'z'nounted on the yoke |65 of the trame |33 (Figs. l and 3)." .'I'he construction and operation of 'the dash pot is the same as that disclosed in the'lcopendingapplication of John W. May and William AH. Btuellein, Serial No. 392,048, illed May 6, 1941, and assigned to the assignee oi' the lnstant invention. For this reason, only a brief description oi' the dash pot is given herein.

` A suction disc 209 (Fig. 3) mounted on the lower end of a vertically disposed rod 2|| cooperates with a suction disc 2 |3 mounted for universal movement in a dash pot 2|5. The disc 208 is secured to the rodv 2|| by means of a screw thread and is prevented from rotating relative thereto by means of a pin 2|1. 'I'he rod 2|| passes through an opening in a circular plate 2|3 which is secured to the yoke |65 by screws 22| the plate serving as a guide for the rod. The enlarged upper end 223 oi the rod 2|| is provided with an open slot 225 engaging a pin 221 supported on land extending between the sides of the tripping lever |13. The enlarged upper end 223 of the rod 2li is slidable longitudinally in a cyl- Upon theocclirrence oi an overload fansdjustmz screw lll; is

Y to

. amature to attracted position to as signed to the assignee geantes inder- 229 pivotally supported on the pin 221 and having' its lower end formed intovan inwardly extending ilange 23|. A compression spring 233 is disposed between the ilange 23| and the enlarged end ot the rod 2|I.

The suction disc 3I3 is mounted i'or universal tilting movement on a spherical bearing molded integral with thebottom of the dashpot 2li. A shouldered screw 235 threaded into thevbearing retains the suction disc 2|3 inplace. and at the same time. permits tilting movemit thereof so that the suction surfaces oi the discawill be accurately aligned when they are brought into engagement. The suction disc 233 is provided with a pair of opposed suction areas which are adapted to cooperate v'with similar suction areas on theface oi' the disc 2|3 to eifect a'time delay tripping on 'overloads below a predetermined magnitude. Provision is made for rotating the disc 2|3 relative to the disc 203 in order to vary the time delay overloads. The dash pot and Vthe yoke |65. The spring clips 231 are iormed in a manner to cooperate with annular projections 24| on the periphery o! the dash pot 2|3. The i'orce exerted by the spring clips 231 on thebe'veled portions of the projections!" press the rdash pot into engagement witiran annular gasket 243 to form an oil seal and at the same timepermit" manual rotatlonfoi the dash pot; tation of the dash pot ls communicated tothe disc 2|3 by` means'oi projections 2|! molded ln- |aegral""withthe' bottom oi the dash pot'and projecting into openings in. the disc.- By rotating the dash pot 2li. thesuction dise 2I3 is rotated relative to the suctiondisc 203 and thus the area of engagement of the suction surfaces 'is varied to provide for a longer Yor shorter time delay' depending upon the extent oi' disp t 'ofthe suction surfaces.

Upon the 'occurrence o! overload currentsbelow' afpredetermined value tor example below 100095 of normal current for which the breaker s l'attracts the armature is rated, the'magnet i3 |19 witha i'orcesumcient to overcome the tension or the springsV |3`| undatingthrough the cylinder 228 and spring 233, applies a pressure to the enlarged end'223grof the rod '2|| in anupward direction. This pressure, after a time delay, breaks the suction seal between the discs 203 and 2|3 whereupon the Vmagnet ISI -moves the rocking the trip lever |13 counter-clockwise to eiIect" tripping oi' the breaker in the previously described manner.

Upon the occurrence oi an overload above the predetermined value or a short circuit, the magnetic pull is sumcient to cause instantaneous tripping of the breaker. Under this circumstance, the trip lever |13 is operated instantaneously compressing the spring 233 without waiting for the force applied to the rod 2|| to break the suction seal between the discs. The springs |2| act to restore the trip lever |13 to its normal position as soon as the contacts are opened and the magnet IBI deenergized.

The construction oi the circuit breaker as thus far described in detail is substantially the same that fully disclosed in the copending application of John W. May and William H. Stuellein, Serial No. 392,048, filed May 6, 1941, and aso! the instant invention.

r In certain installations of circuit breakers embodying the above described trip device, the

' `Larnaca breakers, including the trip devices, are ,often subjected to shocks of such magnitude as to cause movement of the trip levers to trip the breaker. In such cases, the circuits controlled by the breakers are interrupted and serious consequences may result. Normal current owing through the circuit of the breaker energizes the trip' magnet Ill (Figs. l and 3)V which attractsl fthe armature |19 butnot suiiciently to alone overcome theY springs |9l and cause tripping of `the breaker. II.' however, the breaker is subjected to a'jarring iorce'the armature might be moved closer to the magnet |6| thus reducing the magnetic air gap to an extent that the magnet, under normal circuit conditions, would attract the amature and cause undesirable and Vfalse tripping of the breaker. n d Y l 'In order to prevent accidental movement of the armature |19 and 'consequently Vthetrip lever |12 towardtripping position in response to jar` ring Vmrcesthex'e'is provided a pair o! relatively heavy. dynamically4 unbalanced latches 241 and I" Fig's. 2, 3 4).: The latches 2" and 249 are pivotally-supported by means 'of shoulr dered pivot pinsmli `and '253, respectivelyfon the side membersiillof the't'rip device frame.

the sides of the triplever 415;'*CI'he latches are disposed each reversed from the other and light springs 205 and!" are provided of just suiilcient strength to overcome the gravity unbalanced weight of the latches and maintain the latches in static position regardless of any tilted position ci' the breaker. The springs 265 and 281 which abut against the yoke |65 and are seated in spring seats in their respective latches, bias the latches against the yoke IG5. in which position the pin 221 is free to move in tripping direction between the hook shaped projections 251 and 259. However, if a jarring force is applied to the base oi' the breaker of such magnitude as to cause the amature |18 and the trip lever |12 to move in tripping direction. the jarring force will also be imparted to one or both of the unbalanced latches causing the latch or latches in rotate about their pivots away from the yoke Hl. As the latch rotates the beveled or inP clined face or 2 engages the pin 221. wherenpona binding action occurs between the mass of the armature and the mass of the latch which prevents movement oi' the trip lever |13 in trip- 'ping direction, and thereby prevents a reduction of the magnetic air gap during the existence of the jarring iorce. When the jarring force ceases, the spring 255 and 281, restore their respective latches 241 and 249 to the normal positions.

The inclined surfaces 26| and 263 are so arranged that should a heavy overload or short circuit occur during the existence of a jarring force. the increased energization of the trip magnet IGI will overcome the action of the shock proof latch or latches and move the trip lever to tripping position in response to such short circuit conditions.

From the foregoing it can be seen that there has been provided a shock proof device which s aime c v V'prevents tripping movement of the trip lever in response to shocks or jarring forces only during the existence of such jarring forces and which does not obstruct normal operation oi' the trip lever in response to overload circuit conditions.

. There .has been provided a shock proof device which comprises but two essential parts which are simple and rugged, and which may be readily applied to many standard forms oi circuit breaker 1u structures.

Having described the preferred embodiment of the invention in accordance with the patent statutes. ,it is to be understooduhthatvarious changes and modications may be made in the ,structural'details disclosed without departing from vsoxne ofthe essential features of the invention. "It isythereiore. desired that ,the language of the appended claims be given as 'reasonably broad interprtation as the prior art 2u L `I claim as lmy invention:

l: Ina' circuit breaker, contact means, means for ac tuatlngsaid contact means tol an open or to a closed position. a'trip'device includinga .trip f lever 'operablefto `a tripping positionktcjcause 25, movementlo'fthe ,contact means toopen position .in #espesa @predetermined shag-mal amatissj''ditiqnsfand'akhock prooil nians opljablcinire- 'fjsponse togjariing forcesl topreverit finovement of the tripffleveito tripping V,positionj said shock '30" proof"nxe'an`s"`comprising an unbalanced .latch `member-:ino ble 'in response to jarring forces to applilaf, Qelmthegtrip leverfin a Adirection to j ni` einerit ofr'fsaid' tripflev'ergto .tripping "posllilollf` y Y mult breaker.' contact means-actuatipr moving Vsaid contact means to an `"open;`or"tofa;,closed position, amtrip device includingtripmember loperable to a tripping position to cause movement of the contact means to 40 open position in response to predetermined abtrip member in a direction to restrain said. trip member against movement to tripping position.

3. In a circuit breaker. contact means, means i'or actuating said contact means to an open or to a closed position, a trip device including an 5 electromagnet, an armature operable by said electromagnet in response to abnormal circuit conditions to cause movement of the contact means to open position, and a shock proof device comprising an unbalanced latch member operable in response to sudden jarring forces to apply a force to said armature in a direction to oppose operation of the armature and reduction of the magnetic air gap.

4. In a circuit breaker, contact means, actuatving means for moving said contact means to an open and to a closed position, a trip device operable to a tripping position to cause movement of the contact means to open position, a time delay device normally opposing movement of the trip 85 device to tripping position. and a shock prooir device comprising a plurality of unbalanced members each operable in a diilerent, direction from the other in response to sudden jarring forces to apply a force to the trip device in a direction to prevent movement thereof to tripping position by jarring forces.

5. A trip device for a circuit breaker including a trip member movable from a normal position to a tripping position to trip the breaker, and

means normally permitting movement of said trip member and operable in response to and only during the existence oi.' sudden jarring forces to apply a force to the trip member to prevent movement of said trip member to tripping position by jarring forces.

6. A trip device for a circuit breaker comprising a trip member movable from a normal position to a tripping position to cause opening of the breaker. an electromagnet operable in response to predetermined circuit conditions to move said trip member to tripping position, and means operable in response to sudden jarring forces to apply a force to the trip member opposlng movement of said trip member to tripping posltion, said electromagnet being operable in response to predetermined circuit conditions occurring during the existence of a jarring force to overcome the force applied by said opposing means and move the trip member to tripping position.

7. A trip device for a circuit breaker comprising a trip member movable from a normal position to a tripping position to cause opening oi' the breaker. means operable in response to predetermined abnormal' circuit conditions to move the trip member to tripping position, and means comprising a plurality o! independently movable members each operable in response to sudden jarring forces to engage a part movable with the trip member to oppose movement thereof during the existence of jarring forces.

8. A trip device fora circuit breaker comprising a trip member operable to cause opening ot the-breaker, means operable in response to predetermined circuit conditions to operate the trip member, and shock prooi' means comprising a pair oi' independently mounted unbalanced masses disposed for movement in opposite directions. said unbalanced masses each being operable in response to shocks and iarring forces to engage and oppose operation of the trip mem- 9. A trip device for a circuit breaker comprising a trip member operable to cause opening of the breaker, eiectroresponsive means operable in response to predetermined abnormal circuit con- A ditions to operate said trip member, and means ing a trip member having a normal position and operable to a tripping position'to trip the breaker, electro-responsive means operable in response to predetermined circuit conditions to operate said trip member, and a shock proof device comprising a plurality ci pivotally mounted unbalanced masses, s'aid unbalanced masses being disposed for movement in opposite directions and operable in response to sudden jarring forces to apply a i'orce to the trip member opposing movement oi' said trip member to tripping position.

1i. A trip device for a circuit breaker comprising a trip member movable from a normal position to a tripping position to trip the breaker, a plurality of means disposed for movement in opposite directions. said means normally permittlng movement o! the trip member to tripping position and each of said means being independ-l ently operable to prevent movement oi' said trip member in response to and only during the existence of sudden iarrlng forces.

.romv w. MAY. 

